This proposal is designed to train a clinician, specializing in cardiology, in cellular and molecular biology. Core courses from the Ph. D. program in Cell Biology will be taken. In addition, participation in laboratory research meetings, journal clubs and seminars will also be an integral part of the formal training. The initial laboratory training of Phase I will involve a project investigating the structure and function relationship of the myosin tail (see enclosed research proposal for Phase I). A gene consisting of a repetitive 28 amino acid sequence encompassing the chemical properties of an alpha-helical coiled-coil and modeled after the conserved pattern seen in the Dictyostelium myosin tail will be synthesized. The gene will be expressed in E. coli. The purified protein will then be analyzed by electron microscopy and biochemical techniques to determine its structure and function. In addition, site-specific mutagenesis will be applied to alter a strongly positive charged region in the Dictyostelium myosin tail to determine its effect on structure and function. The research project of Phase II will extend the findings of Phase I. Specifically, site-specific mutagenesis will be used to study the mechanism of assembly of the myosin tail by altering suspected sites involved in the regulation of the assembly process (i.e., phosphorylation sites).